nitelyechos

i'm trying to work my way through this problem but i dont understand it. HCN is a weak acid and bromine is a good leaving group. so what i have here is a sn1 reaction. right? or is it an e1? the HCN is too weak to substitute the bromine so the bromine has to dissassociate in the first step before the CN- can attack. but what do i do then?

.....CH3..............................................CH3 .....|....................................................| ..I-C-H................+ NaCN...->............CN-C-H.............+.......I- .....|....................................................| HO-C-H..........................................OH-C-H ......|...................................................| ....CH3................................................CH3 i have sneaky suspicion that after the CN takes the place of I it switches around to the back of the carbon chain, opposite the side of the OH, but thats as far as i can get.

as for as i understand in each case the haloalkane would follow the formula R-X + CH3O- CH3OR + X- i dont know how any of the haloalkanes in the list would give any products accept CH3OR + X-, but i do believe that if one of the haloalkanes is an exception to this formula it would be because of the halogen. the halogen would reform with CH3O- and give a product like CH3OX + R or something crazy like that. so am i right that i just need to focus on the halogens? if so my money is on CH2=CH-I since its the only haloalkane listed with iodide.

i understand the halogen is substituted by the nucleophile (CH3O-) in most cases but how do i tell which is the exception? problem: R-X + CH3O- CH3OR + X- which haloalkane would not undergo the reaction above? CH2=CH-CH2-Br CH3Cl CH2=CH-I CH3CH2Br CH3CH2CH2Cl

i tried drawing the bone line structure for 2-cyclopentenol and 3-cyclopentenol which is one of an exercise i am doing for class. i looked up the correct answer and apparently cyclopentenol has a double bond in the carbon ring and the 2 or 3 changes its position. based on the name alone how the heck am i supposed to know that i'm supposed to draw cyclopentenol with a double bond?